/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Globalization;
using Spring.Util;

namespace Spring.Globalization.Formatters;

/// <summary>
/// Implementation of <see cref="IFormatter"/> that can be used to
/// format and parse numbers.
/// </summary>
/// <remarks>
/// <para>
/// <c>PercentFormatter</c> uses percent-related properties of the
/// <see cref="NumberFormatInfo"/> to format and parse percentages.
/// </para>
/// <para>
/// If you use one of the constructors that accept culture as a parameter
/// to create an instance of <c>PercentFormatter</c>, default <c>NumberFormatInfo</c>
/// for the specified culture will be used.
/// </para>
/// <para>
/// You can also use properties exposed by the <c>PercentFormatter</c> in order
/// to override some of the default number formatting parameters.
/// </para>
/// </remarks>
/// <author>Aleksandar Seovic</author>
public class PercentFormatter : IFormatter
{
    private static int[] positivePatterns = new int[] { 3, 1, 0 };
    private static int[] negativePatterns = new int[] { 8, 5, 1 };

    private NumberFormatInfo formatInfo;

    /// <summary>
    /// Initializes a new instance of the <see cref="PercentFormatter"/> class
    /// using default <see cref="NumberFormatInfo"/> for the current thread's culture.
    /// </summary>
    public PercentFormatter() : this(CultureInfo.CurrentCulture)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="PercentFormatter"/> class
    /// using default <see cref="NumberFormatInfo"/> for the specified culture.
    /// </summary>
    /// <param name="cultureName">The culture name.</param>
    public PercentFormatter(string cultureName) : this(CultureInfo.CreateSpecificCulture(cultureName))
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="PercentFormatter"/> class
    /// using default <see cref="NumberFormatInfo"/> for the specified culture.
    /// </summary>
    /// <param name="culture">The culture.</param>
    public PercentFormatter(CultureInfo culture)
    {
        formatInfo = culture.NumberFormat;
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="PercentFormatter"/> class
    /// using specified <see cref="NumberFormatInfo"/>.
    /// </summary>
    /// <param name="formatInfo">
    /// The <see cref="NumberFormatInfo"/> instance that defines how
    /// numbers are formatted and parsed.
    /// </param>
    public PercentFormatter(NumberFormatInfo formatInfo)
    {
        this.formatInfo = formatInfo;
    }

    /// <summary>
    /// Gets or sets the number of decimal digits.
    /// </summary>
    /// <value>The number of decimal digits.</value>
    /// <seealso cref="NumberFormatInfo.PercentDecimalDigits"/>
    public int DecimalDigits
    {
        get { return formatInfo.PercentDecimalDigits; }
        set { formatInfo.PercentDecimalDigits = value; }
    }

    /// <summary>
    /// Gets or sets the decimal separator.
    /// </summary>
    /// <value>The decimal separator.</value>
    /// <seealso cref="NumberFormatInfo.PercentDecimalSeparator"/>
    public string DecimalSeparator
    {
        get { return formatInfo.PercentDecimalSeparator; }
        set { formatInfo.PercentDecimalSeparator = value; }
    }

    /// <summary>
    /// Gets or sets the percent group sizes.
    /// </summary>
    /// <value>The percent group sizes.</value>
    /// <seealso cref="NumberFormatInfo.PercentGroupSizes"/>
    public int[] GroupSizes
    {
        get { return formatInfo.PercentGroupSizes; }
        set { formatInfo.PercentGroupSizes = value; }
    }

    /// <summary>
    /// Gets or sets the percent group separator.
    /// </summary>
    /// <value>The percent group separator.</value>
    /// <seealso cref="NumberFormatInfo.PercentGroupSeparator"/>
    public string GroupSeparator
    {
        get { return formatInfo.PercentGroupSeparator; }
        set { formatInfo.PercentGroupSeparator = value; }
    }

    /// <summary>
    /// Gets or sets the negative pattern.
    /// </summary>
    /// <value>The percent negative pattern.</value>
    /// <seealso cref="NumberFormatInfo.PercentNegativePattern"/>
    public int NegativePattern
    {
        get { return formatInfo.PercentNegativePattern; }
        set { formatInfo.PercentNegativePattern = value; }
    }

    /// <summary>
    /// Gets or sets the positive pattern.
    /// </summary>
    /// <value>The percent positive pattern.</value>
    /// <seealso cref="NumberFormatInfo.PercentPositivePattern"/>
    public int PositivePattern
    {
        get { return formatInfo.PercentPositivePattern; }
        set { formatInfo.PercentPositivePattern = value; }
    }

    /// <summary>
    /// Gets or sets the percent symbol.
    /// </summary>
    /// <value>The percent symbol.</value>
    /// <seealso cref="NumberFormatInfo.PercentSymbol"/>
    public string PercentSymbol
    {
        get { return formatInfo.PercentSymbol; }
        set { formatInfo.PercentSymbol = value; }
    }

    /// <summary>
    /// Gets or sets the per mille symbol.
    /// </summary>
    /// <value>The per mille symbol.</value>
    /// <seealso cref="NumberFormatInfo.PerMilleSymbol"/>
    public string PerMilleSymbol
    {
        get { return formatInfo.PerMilleSymbol; }
        set { formatInfo.PerMilleSymbol = value; }
    }

    /// <summary>
    /// Formats the specified percentage value.
    /// </summary>
    /// <param name="value">The value to format.</param>
    /// <returns>Formatted percentage.</returns>
    /// <exception cref="ArgumentNullException">If <paramref name="value"/> is <c>null</c>.</exception>
    /// <exception cref="ArgumentException">If <paramref name="value"/> is not a number.</exception>
    public string Format(object value)
    {
        AssertUtils.ArgumentNotNull(value, "value");
        if (!NumberUtils.IsNumber(value))
        {
            throw new ArgumentException("PercentFormatter can only be used to format numbers.");
        }

        return String.Format(formatInfo, "{0:P}", value);
    }

    /// <summary>
    /// Parses the specified percentage value.
    /// </summary>
    /// <param name="value">The percentage value to parse.</param>
    /// <returns>Parsed percentage value as a <see cref="Double"/>.</returns>
    public object Parse(string value)
    {
        if (!StringUtils.HasText(value))
        {
            return 0d;
        }

        // there is no percentage parser in .NET, so we use currency parser to achieve the goal
        NumberFormatInfo fi = (NumberFormatInfo) formatInfo.Clone();
        fi.CurrencyDecimalDigits = formatInfo.PercentDecimalDigits;
        fi.CurrencyDecimalSeparator = formatInfo.PercentDecimalSeparator;
        fi.CurrencyGroupSeparator = formatInfo.PercentGroupSeparator;
        fi.CurrencyGroupSizes = formatInfo.PercentGroupSizes;
        fi.CurrencyNegativePattern = negativePatterns[formatInfo.PercentNegativePattern];
        fi.CurrencyPositivePattern = positivePatterns[formatInfo.PercentPositivePattern];
        fi.CurrencySymbol = formatInfo.PercentSymbol;

        return Double.Parse(value, NumberStyles.Currency, fi) / 100;
    }
}
